Citrix or Desktops

Hi Guys, hope you can help…

We are looking at two routes, Citrix with slim clients or Desktops, and just upgrading the PC’s to Windows7 when it comes out, and upgrading servers to 2008.

Does anyone have any advice, where to look, things to watch out for and do?

Any help or pointers would be great.

Thanks in Advance

Steff Keightley